zulip-electron-updater-and-launcher: add script.

Script will install or update all npm dependancies to run
zulip-electron.
Fixes: #77.

zulip-electron-updater-and-launcher.sh

@@ -0,0 +1,111 @@
+#!/bin/bash
+
+# Zulip Beta Client Launcher
+
+# This script ensures that you have the latest version of the specified branch
+# (defaults to master if none specified) and then updates or installs all your
+# required npm modules.
+
+# I recommend symlinking this script into your PATH.
+
+# {{{ showUsage()
+
+showUsage()
+{
+	echo "Usage: $0 <branch_name>"
+	echo "Example: $0 dev"
+	exit 1
+}
+
+# }}}
+# {{{ envSetup()
+
+envSetup()
+{
+	defaultBranch="master"
+	startingDir=`pwd`
+	requirePop=0
+
+	# Check command line arguments
+	if [ "$#" -gt "1" ]
+	then
+		showUsage
+	elif [ "$#" -eq "1" ]
+	then
+		myBranch=$1
+	else
+		myBranch=$defaultBranch
+	fi
+
+	# Set workingDir
+	if [ -L $0 ]
+	then
+		realPath=`ls -l $0 | cut -d '>' -f 2`
+		workingDir=`dirname $realPath`
+	else
+		workingDir="."
+	fi
+
+	# Set name of upstreamRemote and startingBranch
+	cd $workingDir
+	startingBranch=`git branch | grep \* | cut -d ' ' -f 2`
+	git remote -v | grep "github\.com.zulip.zulip-electron.git (fetch)" > /dev/null 2>&1
+	if [ $? -eq 0 ]
+	then
+		upstreamRemote=`git remote -v | grep "github\.com.zulip.zulip-electron.git (fetch)" | awk '{ print $1 }'`
+	else
+		upstreamRemote="origin"
+	fi
+}
+
+# }}}
+# {{{ gitCheckout()
+
+gitCheckout()
+{
+	git fetch $upstreamRemote
+	git checkout $myBranch
+	git pull --rebase $upstreamRemote master
+	if [ $? -gt 0 ]
+	then
+		echo "Stashing uncommitted changes and doing a new git pull"
+		git stash && requirePop=1
+		git pull --rebase $upstreamRemote master
+
+	fi
+}
+
+# }}}
+# {{{ npmUpgradeStart()
+
+npmUpgradeStart()
+{
+	npm upgrade
+	npm start &
+}
+
+# }}}
+# {{{ cleanUp()
+
+cleanUp()
+{
+	# Switch back to branch we started on
+	git checkout $startingBranch
+
+	# Pop if we stashed
+	if [ $requirePop -eq 1 ]
+	then
+		echo "Popping out uncommitted changes"
+		git stash pop
+	fi
+
+	# Return the whatever dir we started in
+	cd $startingDir
+}
+
+# }}}
+
+envSetup $*
+gitCheckout
+npmUpgradeStart
+cleanUp